Corticospinal tract degeneration and temporal lobe atrophy in frontotemporal lobar degeneration TDP-43 type C pathology.

Frontotemporal lobar degeneration (FTLD) consists of a clinically, pathologically and genetically heterogeneous group of neurodegenerative disorders that chiefly affect frontal and temporal lobes. Clinical presentation in FTLD includes behavioural variant frontotemporal dementia, progressive nonfluent aphasia and semantic dementia (SD). Pathologically, FTLD is subdivided based on accumulation of abnormal intracellular proteins including transactivation response DNA-binding protein 43 kDa (TDP-43) [1, 2]. TDP-43 pathology in FTLD is classified into five pathological subgroups depending on its morphological features: TDP-43 type A, B, C, D and E [2, 3].